On Mon, 12 Dec 2005, Peter Dalgaard wrote:
Prof Brian Ripley <[EMAIL PROTECTED]> writes:
On Mon, 12 Dec 2005, ronggui wrote:
x<-as.Date(c("2005-07-01", "2005-07-02","2005-07-03","2005-07-04","2005-07-05"))
weekdays(x)
[1] "ÐÇÆÚÎå" "ÐÇÆÚÁù" "ÐÇÆÚÈÕ" "ÐÇÆÚÒ»" "ÐÇÆÚ¶þ"
months(x)
[1] "ÆßÔÂ" "ÆßÔÂ" "ÆßÔÂ" "ÆßÔÂ" "ÆßÔÂ"
He asked for week numbers. That's nothing like as easy, as it is not
well-defined. But
strftime(as.POSIXlt(x), "%U")
[1] "26" "26" "27" "27" "27"
is one possibility ("%W" is another). This approach will do the other
requests just as easily.
%W seems to be what is known as "ISO dates" (week starts on Monday),
except that
strftime(as.POSIXlt(as.Date("2005-01-01")), "%U")
[1] "00"
should be week 53, 2004 according to my printed calendar, and emacs
calendar-mode too.
I _did_ say
That's nothing like as easy, as it is not well-defined.
The POSIX definition is
%U
Replaced by the week number of the year as a decimal number [00,53].
The first Sunday of January is the first day of week 1; days in the
new year before this are in week 0.
%W
Replaced by the week number of the year as a decimal number [00,53].
The first Monday of January is the first day of week 1; days in the
new year before this are in week 0.
so it is doing what it is documented to do. I'd take POSIX as more
definitive than Emacs ....
--
Brian D. Ripley, [EMAIL PROTECTED]
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595
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